/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package javax.swing;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.beans.PropertyChangeListener;
import java.util.Locale;
import java.util.Vector;

import javax.accessibility.*;

/**
 * This class is inserted in between cell renderers and the components that
 * use them.  It just exists to thwart the repaint() and invalidate() methods
 * which would otherwise propagate up the tree when the renderer was configured.
 * It's used by the implementations of JTable, JTree, and JList.  For example,
 * here's how CellRendererPane is used in the code the paints each row
 * in a JList:
 * <pre>
 *   cellRendererPane = new CellRendererPane();
 *   ...
 *   Component rendererComponent = renderer.getListCellRendererComponent();
 *   renderer.configureListCellRenderer(dataModel.getElementAt(row), row);
 *   cellRendererPane.paintComponent(g, rendererComponent, this, x, y, w, h);
 * </pre>
 * <p>
 * A renderer component must override isShowing() and unconditionally return
 * true to work correctly because the Swing paint does nothing for components
 * with isShowing false.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Hans Muller
 */
public class CellRendererPane extends Container implements Accessible {

  /**
   * Construct a CellRendererPane object.
   */
  public CellRendererPane() {
    super();
    setLayout(null);
    setVisible(false);
  }

  /**
   * Overridden to avoid propagating a invalidate up the tree when the
   * cell renderer child is configured.
   */
  public void invalidate() {
  }


  /**
   * Shouldn't be called.
   */
  public void paint(Graphics g) {
  }


  /**
   * Shouldn't be called.
   */
  public void update(Graphics g) {
  }


  /**
   * If the specified component is already a child of this then we don't
   * bother doing anything - stacking order doesn't matter for cell
   * renderer components (CellRendererPane doesn't paint anyway).
   */
  protected void addImpl(Component x, Object constraints, int index) {
    if (x.getParent() == this) {
      return;
    } else {
      super.addImpl(x, constraints, index);
    }
  }


  /**
   * Paint a cell renderer component c on graphics object g.  Before the component
   * is drawn it's reparented to this (if that's necessary), it's bounds
   * are set to w,h and the graphics object is (effectively) translated to x,y.
   * If it's a JComponent, double buffering is temporarily turned off. After
   * the component is painted it's bounds are reset to -w, -h, 0, 0 so that, if
   * it's the last renderer component painted, it will not start consuming input.
   * The Container p is the component we're actually drawing on, typically it's
   * equal to this.getParent(). If shouldValidate is true the component c will be
   * validated before painted.
   */
  public void paintComponent(Graphics g, Component c, Container p, int x, int y, int w, int h,
      boolean shouldValidate) {
    if (c == null) {
      if (p != null) {
        Color oldColor = g.getColor();
        g.setColor(p.getBackground());
        g.fillRect(x, y, w, h);
        g.setColor(oldColor);
      }
      return;
    }

    if (c.getParent() != this) {
      this.add(c);
    }

    c.setBounds(x, y, w, h);

    if (shouldValidate) {
      c.validate();
    }

    boolean wasDoubleBuffered = false;
    if ((c instanceof JComponent) && ((JComponent) c).isDoubleBuffered()) {
      wasDoubleBuffered = true;
      ((JComponent) c).setDoubleBuffered(false);
    }

    Graphics cg = g.create(x, y, w, h);
    try {
      c.paint(cg);
    } finally {
      cg.dispose();
    }

    if (wasDoubleBuffered && (c instanceof JComponent)) {
      ((JComponent) c).setDoubleBuffered(true);
    }

    c.setBounds(-w, -h, 0, 0);
  }


  /**
   * Calls this.paintComponent(g, c, p, x, y, w, h, false).
   */
  public void paintComponent(Graphics g, Component c, Container p, int x, int y, int w, int h) {
    paintComponent(g, c, p, x, y, w, h, false);
  }


  /**
   * Calls this.paintComponent() with the rectangles x,y,width,height fields.
   */
  public void paintComponent(Graphics g, Component c, Container p, Rectangle r) {
    paintComponent(g, c, p, r.x, r.y, r.width, r.height);
  }


  private void writeObject(ObjectOutputStream s) throws IOException {
    removeAll();
    s.defaultWriteObject();
  }

/////////////////
// Accessibility support
////////////////

  protected AccessibleContext accessibleContext = null;

  /**
   * Gets the AccessibleContext associated with this CellRendererPane.
   * For CellRendererPanes, the AccessibleContext takes the form of an
   * AccessibleCellRendererPane.
   * A new AccessibleCellRendererPane instance is created if necessary.
   *
   * @return an AccessibleCellRendererPane that serves as the AccessibleContext of this
   * CellRendererPane
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleCellRendererPane();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>CellRendererPane</code> class.
   */
  protected class AccessibleCellRendererPane extends AccessibleAWTContainer {
    // AccessibleContext methods
    //

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     * @see AccessibleRole
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.PANEL;
    }
  } // inner class AccessibleCellRendererPane
}
